It applies to the field of data processing operations in an industrial environment and particularly to data processing systems of the “open” type running, for example, on software of the “UNIX” or “WINDOWS NT” type. The servers that run on this type of software are called “open” servers, and are highly valued at the present time.
The drawback of these servers is that they were developed for academic applications whose purposes were not the same as those for industrial purposes. Thus, in a “UNIX” operating system, the jobs, or more precisely each of the processes comprising the jobs are assigned an initial priority, either by the system or by the user who enters these jobs. In order for a job to be considered by the system to have a higher priority, the user must explicitly assign it an initial priority, or manually modify its priority using an administrative command. Thus, there is no control over or inter-correlation between the priority levels assigned to one job or another.
Likewise, in a standard “UNIX” system, the processes can start up without any limitation, even in heavily loaded systems, without any attention to the number of resources currently being used by the processes executed and without any attention to the number of resources the new process will require. This results in the following disadvantage a group of processes is executed, the critical processes as well as the non-critical processes, and the critical processes, which must be completed at a time desired by the user, have too few resources available to be completed at the desired time. At the same time, non-critical processes are using too many resources.
Another disadvantage in known systems is that in which there are not enough temporary files available and consequently, the write operations into the files fail. Sometimes, the application controls this error condition, sometimes it does not control it, and this can generate a false indication due to the fact that incomplete files are generated in one step of a job and processed in subsequent steps. Another detrimental characteristic is that in which there is not enough paging space and the system makes the arbitrary decision to kill the most recent process without considering its importance. This is unacceptable in an operating environment.